Procedures will be developed for permanently inserting genes from any source into plasmids and viruses. Bacterial plasmids containing specific eukaryotic genes including genes for immunoglobulin synthesis will be constructed, and the expression of the eukaryotic genes in Escherichia coli will be studied. In brief, the method involves ligating specific EcoRI restricting nuclease fragments of DNA (from any source) to specific EcoRI-treated plasmid DNA, and transforming E. coli with the constructed plasmid. In addition to developing a new mechanism for adding any selected genes to bacteria, this work also serves as a pilot study for the potential use of the tumor viruses SV40 and polyoma or other carriers as vehicles for gene addition to eukaryotic cells.